Derivatives of 7{60 -methylestr-4-en-3{60 ,17{62 -diol

ABSTRACT

7 Alpha -Methylestr-4-ene-3 Alpha , 17 Beta -diol and derivatives thereof useful as antifertility agents.

United States Patent [1 1 Grunwell et a].

DERIVATIVES OF 7a-METHYLES'I'R-4-EN-3oql7B-DIOL Inventors: Joyce F.Grunwell, Hamilton;

Harvey D. Benson, Cincinnati, both of Ohio Assignee: Richardson-Merrelllnc., filton,

Conn.

Filed: Nov. 1, 1973 Appl. No.: 411,791

US. Cl... 260/397.5; 260/239.55 R; 260/3974;

2 424/243; 424/238 Int. Cl. C071 17/ 0 Field M Search "260/3915 Dec. 23,1975 References Cited UNITED STATES PATENTS 7/1966 l/l967 7/1967 5/1968l/l969 ll/I974 Primary Examiner-Elbert L. Roberts Attorney, Agent, orFirm-William J. Stein; Eugene O. Retter; George W. Rauchfixss, Jr.

7a-Methylestr-4-ene-3a,

ABSTRACT l'l fi-diol and derivatives thereof useful as antifertilityagents.

4 Claims, No Drawings DERIVATIVES OF 7 a-METHYLESTR-4-EN-3 11,17 B-DIOLFIELD OF THE INVENTION This invention relates to 7a-methylestr-4-ene-3a,l7B dil and novel derivatives thereof, to their preparation and totheir usefulness as antiprogestational and antifertility agents.

BACKGROUND OF THE INVENTION the blastocyst or results in the subsequentexpulsion of a newly implanted blastocyst.

Applicants have made the important discovery that the compounds of thepresent invention exhibit marked antiprogestational and antifertilityproperties without substantial interference with other biologicalprocesses. Thus, under certain dosage regimens, as for example, a daily,low-dosage regimen, the instant com pounds are able to reduce fertilityin mammals as a consequence of their antiprogestational activity withoutinterfering with normal ovulation. In this regard these compounds differfrom the contraceptive steroids of the prior art which function byinhibiting ovulation, by interfering with ovum transport or by virtue oftheir progestational and/or estrogenic properties.

Administration of the antiprogestational agents of the present inventionduring the normal menstrual cycle of primates apparently causes adesynchronization of the maturing uterine mucosa relative to the processof ovulation, thereby preventing implantation or nidation of thefertilized ovum. Thus, in women, for example, the withdrawal ofprogesterone from a progesterone-primed endometriam results in menstrualbleeding. Periodic administration of the antiprogestational agents ofthe present invention, therefore, insures menstrual cyclicity in women,even when administered subsequent to ovulation.

DESCRIPTION OF PRIOR ART US. Pat. No. 3,301,879 represents the closestart known to applicants and discloses a series of la-loweralkyl-4-estrene-3fi,l7/3-diols as anabolic, androgenic agents,antigonadotropic agents, gestagenic agents and anti-hypercholesterinemicagents and specifically discloses the compoundA-3:l7-dihydroxy-7a-methyl-l 9- norandrostene.

All of the compounds described in U.S. Pat. No. 3,30l ,879 containeither a substituent in the 3-position whose stereochemistry is notdesigned, or contain a substituent in the 3-position which isspecifically designated as being in the B-configuration. None of thespecies described therein have a 3-substituent designated to be in thea-congifuration. These compounds are prepared by reducing the4-estren-3-one with a complex light metal hydride, as for example,lithium, sodium, potassium or calcium borohydride, or the 4 estren-3-onecan be reduced with lithium aluminum hydride or an alkalitriloweralkoxyboron or aluminum hydride, such as sodiumtrimethoxyborohydride or lithium tri-tertiarybutoxyaluminum hydride.Such reagents are known to predominately produce the 3B- equatorialisomer, cf., Reduction of 3-keto-A'-steroids with lithium aluminumhydride, sodium borohydride, and lithium tri-t-butoxyaluminum hydride,Fried and Edwards, Organic Reactions in Steroid Chemistry, Volume l, pp.-81, Van Nostrand, Reinhold Company, 1972.

U.S. Pat. No. 3,413,287 discloses a series of (optionally llalkylated)7a-methyl-4-estrene-3B,l7B-diols as anabolic, androgenic, estrogenic andantiestrogenic agents. These compounds are essentially prepared in thesame manner as the compounds described in US. Pat. No. 3,301,879 above,i.e., the reduction of 7amethylestr-4-en-3-ones using a metallicreducing agent such as lithium aluminum hydride, sodium borohydride,lithium tri(tertiarybutoxy)aluminum hydride or diisobutylaluminumhydride to form the 3B-hydroxy- 4-ene derivatives. No compounds weredisclosed having a 3-substituent in the cur-configuration. Example l,for example, specifically describes the preparation of7a-methylestr-4-ene-3B,l 7B-diol, melting at 99-l0lC.

The use of sodium trialkylborohydride as a reducing agent is known.Brown and Krishnamurthy, J. Amer. Chem. Soc., 94, 7159 (I972) and Brown,ibid, 95, 4100 (1973), teach the use of a hindered lithiumtrisec-butylborohydride as a stereoselective reducing agent for certainmonocyclic and bicyclic ketones. The monocyclic ketones describedtherein are relatively simple alkyl-substituted cyclopentanones andcyclohexanones. Only two bicyclic ketones were reduced, namely, camphorand norcamphor, which are unrelated to the 3-oxo steroids being reducedin accordance with the present invention.

SUMMARY OF THE INVENTION wherein each R is selected from the groupconsisting of hydrogen, acyl having from I to 12 carbon atoms,trialkylsilyl in which the alkyl group contains from 1 to 4 carbonatoms, l-cycloalkenyl having from 5 to 8 carbon atoms,l-methoxycycloalkyl and l-ethoxycycloalkyl in which the cycloalkyl grouphas from 5 to 8 carbon atoms and Z-tetrahydropyranyl.

in general the compounds of the present invention are prepared by thereduction of the corresponding l7fl-hydroxy-7a-methylestr-4-en-3-oneusing a highly hindered lithium trialkylborohydride.

A variety of compositions and methods for the control of fertilityutilizing these novel compounds are also included within the scope ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION As illustrated by general Formula(I) above, the novel compounds of the present invention all share a7-methyl substituent which is in the (ii-configuration of the class ofestrane steroids. Additionally, these compounds all have an unsaturationpresent in the 4-posi tion and share hydroxyl groups or substitutedhydroxyl groups in the 3a and l7fi-configurations. Consequently, all ofthe instant compounds can be considered either as7a-methylestr-4-ene-3a,l7B-diols or derivatives thereof, moreparticularly certain monoand di-ester and ether derivatives thereof.

As seen from the description of general Formula (1) above, both hydroxylgroups can be unsubstituted, as in the case of the parent compound7a-methylestr-4-ene- 301,1 'lfi-diol. Alternatively, one of the hydroxylgroups can be substituted as for example, 3a-acetoxy-l7i3-hydroxy-7a-methylestr-4-ene or 3oi-hydroxy-l7B-acetoxy-Ta-methylestr-4-ene; or both of the hydroxyl groups may besubstituted, as for example, the compound301,17B-diacetoxy-7a-methylestr-4-ene.

The acyl esters which are present are obtained from hydrocarbon acylradicals having from I to 12 carbon atoms inclusively. The organic acylgroups include those of saturated and unsaturated aliphatic acids andaromatic acids such as formic, acetic, propionic, butyric, isobutyric,valeric, isovaleric, caproic, caprylic, decanoic, dodecanoic, acrylic,crotonic, cyclobutanecarboxylic, cyclopentanecarboxylic,cyclopentenecarboxylic, cyclohexanecarboxylic, benzoic, toluic,naphthoic, ethylbenzoic, phenylacetic, naphthaleneacetic, phenylvaleric,cinnamic, phenylpropionic, p-propyloxyphenylpropionic andp-butyloxyphenylacetic acid.

The ether derivatives which are present include unsaturated cycloalkaneethers having from to 8 carbon atoms in which the unsaturation ispresent in a position or to the ether oxygen. Illustrative of suchunsaturated ethers are the l-cyclopentene, Lcyclohexene, or 1-cyclooctene radicals. in addition, the corresponding saturatedcycloalkanes are also included within the scope of this inventionwherein the cycloalkane group is substituted with a methoxy or ethoxyradical at its point of attachment. Illustrative of such saturatedsubstituted cycloalkane ethers are: 7a-methyl-l7B-(l'-methoxycycloperityloxy)-4-estren-3a-ol, "Ia-methyl- 3a,l7,B-di( lethoxycyclohexyloxy)-4-estrene, and 7amethyl-3o:-( l-methoxycyclohexyloxy)-4-estrenl 78- ol acetate. Included within theclass of ether derivatives are the saturated heterocyclicZ-tetrahydropyranyl ethers, as for example,7a-methyl-l7B-(2-tetrahydropyranyloxy)-4-estren-3a-ol. Lastly, thetrialkylsilyl ethers such as the trimethylsilyl and dimethylt-butylsilyl ethers are also included within the purview of the presentinvention, as for example the compounds 70:-methyl-l7fl-trimethylsiloxy-4-estren-3a-ol and 7amethyl-3a,l 7B-di(trimethylsiloxy)-4-estrene.

The following compounds further illustrate the species represented bygeneral Formula I above: 7amethylestr-4-ene-3a,l7B-diol B-acetate,7a-methyll7B-( 2'-tetrahydropyranyloxy)estr-4-en-3a-ol, 3a-( lcyclopentenyloxy)-7a-rriethylestr-4-en- 1 73-01, 70:-methylestr-4-ene-3a,l 7B-diol l7-heptanoate, 17B-( 1-methoxycyclohexyloxy)-7a-methylestr-4-en-3a-ol, 3a-(l'-cyclohexenyloxy)-7a-methylestr-4-en-3a-ol 3- butyrate,7a-methylestr-4-ene-3a,l7/3-diol 3,l7-dipropionate,7a-methyl-3o:,l7B-di(2-tetrahydropyranylox y)estr-4-ene, 3a-( 1'-ethoxycycloheptyloxy)Jamethylestr-4-enl 7B-ol l'I-acetate,7a-methyl-3atrimethylsilyloxyestr-4-en-l 7B-ol, 7a-methylestr-4-ene3a,l7B-diol 3dodecanoate, and 7a-methyl-3a,l7B-di(trimethylsilyloxy)estra-4-ene.

The preferred compound of the present invention is7a-methylestr-4-ene-3a,l7B-diol. Applicants have discovered a novelprocess for the reduction of 17B- hydroxy'7a-methylestr-4-en-3-one usinga highly hindered lithium trialkylborohydride which produces theBa-hydroxy isomer. This compound is closely related to the corresponding3B-hydroxy isomer known to the prior art in the references previouslycited. in accordance with the teachings of Example 2 of U.S. Pat. No.3,301,879, a crude crystalline A-3:l7-dihydroxy-70zmethyl-l9-norandrostene" would be obtained. This equivocally identifiedcompound is in reality the compound A 3B,l 7/3-dihydroxy-7a-methyll9-norandrostene, or using applicants preferred system of nomenclature,the compound, 7a-methylestr-4-ene-3B,l7B- diol. A comparison withExample I of the same patent in which a similar reduction is conductedon the 701,] 7a-dimethyl analogue would lead a person having ordinaryskill in the art to believe that the 3B-isomer is obtained inasmuch asExample I specifically indicates the configuration of the product to bein the 3fl-position. Additionally, Example 1 of U.S. Pat. No. 3,4l3,287specifically teaches the preparation of 7amethylestr-4-ene-3B,l7B-diol,having a melting point of 99l0 1C, using essentially the same startingmaterial and reduction procedure. Although traces of the 3oi-hydroxyisomer may be present in the reaction mixtures of the prior art, the artis devoid of any suggestion of the preparation and isolation or of theadvantages obtained with the essentially pure Sa-hydroxy isomer.

The 7oz-methylestr-4-en-3a,l7B-diol is readily prepared by the reductionof the corresponding 4-estren- 3one using a highly hindered lithiumtrialkylborohydride. By the term highly hindered is meant a large oi'bulky organic radical which imparts an enzyme-l ke stereoselectivity tothe reducing agent. The highly hindered nature of this class of reducingagents is essential in order to achieve a stereoselective reduction tothe 3a-hydroxy isomer. Generally speaking, the more hindered the reagentbecomes, the greater its degree of stereoselectivity with, however, aconcommitant loss in reaction rates. The reduction is not considered tobe a true stereospecific reduction inasmuch as some of the SB-hydroxyisomer is also obtained. Nevertheless, these highly hinderedtrialkylborohydridesare selective nucleophilic reducing agents whichWill reduce the 3- ketones with simple efficiency and with a high degreeof stereoselectivity to provide a ready means for the preparation of thedifficultly obtainable 3a-hydroxy isomers. Illustrative of the highlyhindered reducing agents which may be employed are the lithium orpotassium salts of tri-t-butylborohydride, tri -sec -arnylborohydride,and tri-isopropylborohydride with lithium tri-sec-butylborohydride beingthe specific agent of choice. These nucleophilic reagents reduce4-estren- 3-ones with simple efficiency and with a high degree ofstereoselectivity.

The trialkylborohydride reducing agents of this nvention are prepared bymeans of an exchange reaction in which a highly hindered trialkylboraneis added to a solution of lithium or potassium trimethoxyaluminohydride.The lithium trimethoxyaluminohydride reagent is prepared by the additionof 3 moles of methanol to l mole of lithium aluminum hydride in anappropriate solvent, as for example, tetrahydrofuran or ether, cf.,Brown and Deck, J. Amer. Chem. Soc. 87, 5620 (I965). The correspondingpotassium trimethoxyaluminohydride reagent is prepared by thesubstitution of potassium aluminum hydride for the lithium aluminumhydride.

The preparation of the lithium trialkylborohydride reagent can beillustrated by the following reaction scheme wherein R represents ahighly hindered alkyl radical:

LiAII'KOMe), (R),B Li( R ),BH Al(OMe), At ambient temperatures thereaction is essentially complete within 15 minutes; lower temperaturesrequire longer reaction times. Manipulations are performed under aninert gas such as nitrogen or argon. Alternatively, the preferredreagent can be prepared by the reaction of t-butyl lithium withtri-sec-butylborane in an appropriate solvent, as for example, ether,tetrahydrofuran, pentane, hexane, heptane or mixtures thereof.

Once the reagent has been prepared, the temperature of the reactionmixture is adjusted and the estr-4en- 3-one is added, generally insolution. The reaction temperature can vary from 78C. to 25C. with thereduction period ranging anywhere from 10 minutes to 8 hours.Preferably, the reduction is-initially conducted at -78C. for a periodof 2 hours and then permitted to warm to C., where it is maintained foranother 2-hour period. After the reduction is complete, the steroidalborane intermediate which forms is hydrolyzed to the correspondingZia-alcohol usingeither an acid or an alkaline hydrolysis; Preferably analkaline hydrolysis is employed, and even more preferably, thehydrolysisis conducted via the dropwise addition of a solution of sodiumhydroxide. An oxidizing agent such as hydrogen peroxide is generallyadded in order to oxidize the remaining tri-organoborane and tofacilitate the separation and removal of the reaction product.

Reduction of l7B-hydroxy-7ct-methylestr-4-en13-one in accordance withthis procedure results in the formation of both the 311,1 7B-diol andthe 35,17B-diol. Separation of these isomers is achieved by fractionalcrystallization in ether, theJB-hydrbxy isomer initially crys* tallizingfrom solution, whereas the 3or-hydroxy isomer remains inthe filtrate.Chromatographic purification of the filtrate using a silica gel columni'eSults in the isolation and preparation of appreciable quantities ofessen tially pure 7a-methylestr-4-e'ne-3a,l7B-diol, as specificallyillustrated in Example 5, as compared to the trace quantities which maybe present in the reaction mixtures of the prior art.

The term essentially pureas usedhereiri refers to the 3a-hydroxy isomerswhich are substantially free of their corresponding 3flhydroxy isomers.More particularly the term essentially pure is used to indicate the factthat the 3a-hydroxy isomers are free of any physiologically significanteffects which may be attributableto the corresponding 3B-hydr0xyisomers.

Specifically, when referring to the compound 70:- methylestr-4ene-3a,l7fl-diol the term essentially pure refers to a material which is atleast 10 times more active as an antifertility agent in the pregnanthamster test than the prior art 7a-methylestr-4-ene-3fl,l7B-di0l whentested on a weight for weight basis. In addition to the enhancedantifertility activity, essentially pure 7amethylestr-4-ene-3a,l7B-diolhas been found to have significantly less associated biologicalendocrine activ- 6 ity as compared to the corresponding 7a-methylestr-4-ene-3,B,l7B-diol. Thus a comparison of these two isomers at theirrespective effective antifertility dosage, indicates the SB-hydroxyisomer to be If) times more potent in its anabolic and androgenic sideeffects and 33 times more potent in its estrogenic side effects than thecorresponding Ba-hydroxy isomers. The separation of endocrine andantifertility activities is a highly desirable goal in the search fornew antifertility agents. Prolonged usage of androgenic steroids inwomen results in hirsutism and voice deepening, whereas the estrogenicnature of endocrinologically active steroids plays an adverse role incertain thrombotic disorders, such as thrombophlebitis and pulmonaryembolism.

The 7a-methylestr-4-ene-3a,l7fl-diol when crystallized from an ethersolution results in the formation of finely-divided, white crystallineplatelets. A comparison of the essentially pure 3a-hydroxy and3fi-hydroxy isomers, crystallized from ether solutions, shows the3a-hydroxy isomers to melt at a temperature of 17 l-6., whereas theBB-hydroxy isomers melts at a temperature of 99l0lC. Further, acomparison of the nuclear magnetic resonance spectra of these twoisomers in completely deuterated dimethylsulfoxide shows a broad doubletat 5.38 6 for the 4-vinyl hydrogen in the 3a-hydroxy isomer, whereas the3fl-is'omer shows a broad singlet at 5.24 8 for the 4-vinyl-hydro- Bothof the alcohol functions of the 30:, l 7B-positions can be esterified oretherified using standard chemical procedures. if a free l7B-hydroxygroup is present in the starting material, this will also be coesterified or etherified along with the 3a-hydroxy group to yield thecorresponding 3a,l7B-diesters or diethers. The 1713- monoesters andmonoethers are prepared by initially deri'vatizing the l7l3 position andsubsequently reducing the 3-one. The 3a-monoesters and monoethers areprepared by first protecting the l7B-position, reducing the 3-one andderivatizin'g the resulting 3a-hydroxyl group, and subsequently removingthe protecting group from the INS-position. Varying the mixture of theI78- su'bstitution prior to reduction and the Zia-substitutionsubsequent to reduction, results in the formation of mixed esters,ethers and/or ester-ether combinations.

The esters of the present invention are obtained by reacting thehydroxy-steroid with acid anhydrides and acid halides in the presence ofa tertiary organic base such as pyridine or triethylamine. in order toprepare the tetrahydropryanyl ethers, dihydropyran is employed in thepresence of an acid catalyst such as p-toluenesulfonate.

The l-alkoxycycloalkoxy derivatives of the present invention areprepared by reacting the corresponding steroidal alcohols with a loweralkyl ketal of a cycloalkanone or the lower alkylenolether of acycloalkanone or a mixture of both in the presence of an acid catalystsuch as pyridine p-toluene sulfonate in a suitable solvent such asdioxane, t-butanol or methylene chloride. Temperatures employed may varyfrom about 0 to C. with the lower temperatures being preferred to parryout the reaction. Suitable cycloalkyl derivatives include, for example,cyclopentanone, diethylketal and l-methoxyl -cyclohexene. Thel-cycloalkenylethers are prepared directly following essentially thesame procedure but substituting higher boiling reaction solvents inorder to obtain reaction temperatures above 70C. Such solvents includebenzene and dimethylformamide. Alternatively, the l-cycloalkenylethersare prepared by a pyrolysis reaction of the isolated l-alkoxycycloalkoxysteroid in a solvent such as toluene, benzene or dimethylformamide.Using conventional techniques the hydroxyl group can be silylated byreacting the steroid with silylating agents such astrialkylchlorosilane, N-trialkylsilylacetamide in the presence of anamine base such as triethylamine or pyridine.

The highly hindered lithium tri-sec-alkylborohydrides do not reduce anesterified or etherified [7B- hydroxyl group to the correspondingalcohol. As long as the reaction conditions and the subsequent isolationprocedure remain basic, the l7B-ethers remain stable and are retained.The ester groups at the l7B-position may be hydrolyzed or retainedduring the hydrolysis and oxidation workup of the reduction mixture,depending upon the temperature conditions. Temperatures below C. duringthe hydrolysis generally favor retention of the ester group, whereastemperatures above 25C. can result in ester hydrolysis. Thus, by variousesterification and etherification techniques, it is possible to preparecompounds in which the ester or ether derivatives can vary at the and/orl7B-posi tions.

The starting materials utilized in the present invention are thecompound l7B-hydroxy-7a-methylestr-4- en-3-one and its l7B-derivatives.These compounds are available by the reaction of dimethylcopper lithiumwith estr-4,6-dien-3-one in an inert solvent, e.g., ether,tetrahydrofuran, hexane or mixtures thereof, at temperatures which rangefrom -78 to 25C. The enolate which initially forms can be quenched witha strong acid such as dilute hydrochloric acid to form the7amethyl-4-estren-3-one directly. Alternatively, the enolate can bequenched with a weak protonating agent, as for example, ammoniumchloride, to form the 7amethyl-5-estren-3-one, which can then beisomerized I to the 4 ene using either acid or base.

Applicants have discovered that the compounds of the present invention,in particular the compound 7amethyl estr-4-ene-3a,l7fi diol, possessmarked antiprogestational properties which make them useful asantifertility agents. In women, the typical menstrual cycle is 28 dayswith the onset of menstruation counted as day 1. By day 12 of the cyclea mature Graafian follicle is ready to rupture and release an ovum. Inaddition to ovum formation, the follicle also produces estrogen whichstimulates the conversion of the uterine endometrium into itsproliferative phase. On day l4, the ovum is released and the follicle isconverted into the corpus luteum which in addition to estrogen nowproduces progesterone. These two hormones stimulate the endometrialgrowth of the uterine lining converting it by day l9 from itsproliferative phase into its secre tory stage. The ovum is released intothe Fallopian tube and is fertilized shortly thereafter. On about day18% the fertilized ovum enters the uterus, undergoes a per: iod ofuterine migration and by day 21%% to day 24% the ovum or blastocystnidates within the uterine lining and begins to implant. Thisimplantation process is completed with the establishment of thefetal-placental circulation occurring at about day 35. Thus, in orderfor successful implantation to occur, a proper estrogenprogesteronebalance is required during the critical period of uterine migration andblastocyst nidation. Subsequent to implantation, rapid placentaldevelopment occurs and by day 70 to day 75 the placenta now produces allof the progesterone required for the maintenance of pregnancy. Thus, anyinterference with the normal progesterone requirements of a fertilefemale during this critical period following fertilization at about dayl4 to about day at which there is a decline in ovarian dependence forprogesterone, insures the absence of a viable implanted ovum. Byinsuring the absence of an implanted ovum, estrus in fertile femalemammals, or menstrual cyclicity in fertile female primates, includingmonkeys, baboons and humans, is established.

The antiprogestational effect of these compounds is best demonstrated byobserving the decidual cell reaction of a traumatized uterine horn of animmature female rat receiving progesterone. Traumatization of theuterine horn simulates a pseudo-implantation. An increase in tissueweight of the traumatized horn in comparison to the untraumatizedcontralateral control uterine horn, measures progesterone stimulatedgrowth. Conversely, a reduction of this progesteroneprimed decidualresponse is an in vivo biological measure of the antiprogestationalactivity of these compounds.

The effect of these compounds upon nidation and implantation isdemonstrated by their administration to pregnant hamsters at a pointimmediately prior and subsequent to nidation and observing theirprepartum effects. Mated female hamsters, considered to be pregnant bythe presence of sperm in a post-estrus vaginal lavage, are treatedsubcutaneously with the test com; pound during days 3-8 of pregnancy.This period of gestation in the hamster relates in the human from apoint just prior to implantation of a fertilized ovum to a point afterwhich implantation has occurred and placental circulation is nowcomplete. Treated animals are sacrificed l day prior to parturition andthe total number of live feti is ,compared to those in a control groupof mated fertile female hamsters.

The term fertile female mammal as used herein refers to any femalemammal that can reproduce and that requires progesterone forreproduction and gestation. Illustrative of such species are mice, rats,quinea pigs, rabbits, ferrets, dogs, cats, cows, horses and primates,including monkeys, baboons and humans.

The 7a-methylestr-4-ene-3a,l 7B-diols of the present invention arevariously administered in order to achieve their antiprogestationaleffect. In women, they can be administered in small daily doses, Le, aminipill" type of regimen, without inhibiting or interfering with normalovulation. When administered in this fashion, the maturation of theuterine lining is forced out of phase with the ovulation process,thereby preventing nidation or implantation of the fertilized egg.Alternatively, the 7a-methylestr-4-ene-3a,l7B-diols can be administeredin one or more weekly or monthly doses and most effectively during theperiod of from about day 14 to about day '70 from menses.

The contranidative effect of these compounds can be utilized to insurethe failure of a fertilized ovum to implant in any fertile female mammalas previously defined. Thus, the present invention is useful forcontrolling fertility in such commercially valuable species as dogs,cats, cows and horses. Generally, the compounds are administered for aperiod of time not ex ceeding 50% of the gestation period for theparticular species, and preferably these compounds are administeredduring the first quarter of their gestation period.

The particular dosage of the active ingredientdepends upon such factorsas the route of administration, age, weight of the mammal being treatedand the frequency of dosing. Dosage units for treatment in humans usinga mini-pill type of regimen contain from 0.1 mg to 1.0 mg, dependingupon the particular steroid employed. Preferably a dosage unit of from0.1 mg to 0.5 mg, and even more particularly a dosage unit from 0.1 mgto 0.25 mgis employed. A weekly or monthly dosage unit of thetherapeutic steroid contains from about 0.1 mg to about 3.0 g of theactive ingredient per administration with doses repeated as necessary.In the case of a subcutaneous depot preparation or a medicatedintrauterine device, amounts up to 3.0 g of the active ingredient can beadministered once or twice a year.

The compounds of the present invention are administered in variousdosage unit forms such as tablets, capsules, powders, granules, oralsolutions or suspensions, sterile solutions or suspensions forparenteral use, sublingual and intrabuccal preparations, intravaginaland rectal suppositories, vaginal or intrauterine devices impregnatedwith the active ingredient, subcutaneous and intramuscular implants anddepot preparations. The following specific examples further illustratethe invention.

EXAMPLE 1 3 ,17/3-Diacetoxyestr-3 ,5 -diene The compoundl9-nortestosterone, 400 g, is refluxed under nitrogen in a mixture of1500 ml of acetic anhydride and 1500 ml of acetyl chloride for a periodof 3 hours. The volatile solvents are distilled at atmospheric pressureand the final traces of solvent removed under reduced pressure. Thesolid residue which remains is triturated with ice water, filtered,washed with cold aqueous sodium bicarbonate solution, rinsed with waterand dried. Two recrystallizations of this residue from acetone yield 370g of 3,17B-diacetoxyestr-3,5- diene which melts at 16571C.

EXAMPLE 2 17B-Hydroxyestra-4,6-dien-3-one acetate The compound3,17B-diacetoxyestr-3,S-diene, 60.0 g (0.158 mole) prepared as inExample 1, is placed in an acetone buffered solution containing 3,180 mlof acetone, 816 ml of water, 81.6 ml of acetic acid, 18 ml of pyridine,and 81.6 g of sodium acetate. The solution is cooled to -5C. using asalt-methanol-ice bath and 32.1 g (0.18 mole) of N-bromosuccinimide isadded at one time. The reaction mixture is totally shielded from lightand stirring continued for a period of 3 hours at -5C. The solution ispoured onto 12 liters of cold brine and the product extracted with 1liter of ether. The ether extract is washed with water, dried overanhydrous magnesium sulfate and concentrated under vacuum attemperatures below 20C. The amber oil residue is dissolved in 75 ml ofdimethylformamide and rapidly added to a vigorously refluxing suspensionof 750 ml of dimethylformamide, 60 g of lithium bromide and 60 g oflithium carbonate under nitrogen. Residual ether is permitted toevaporate and the reaction mixture is refluxed for a period of 1 hour.0n cooling, the suspension is filtered and the filtrate is poured intoan ice-water mixture. The product is extracted into ether and thecombined ether extracts are washed with water, 2 liters of a sodiumhydroxide solution and washed again with water. The solution is driedover anhydrous magnesium sulfate and concentrated under vacuum to yielda yellow solid which is layered with 10 hexane and filtered to yield34.6 g of the desired 17B- hydroxy-estra-4,6-dien-3-one acetate.

EXAMPLE 3 l7B-Hydroxy-7a-methylestr-4-en-3-one acetate A solution oflithium dimethylcopper is prepared under nitrogen by the addition of 1mole of 1.6 M ethereal methyllithium to a slurry of 99 g (0.52 mole) ofcuprous iodide contained in 1000 ml of anhydrous ether at 0C. Thesolution is stirred at this temperature for 5 minutes and a solution of35 g (0.11 mole) of l7B-hydroxyestra-4,6-dien-3-one acetate, prepared asin Example 2, contained in 300 ml of anhydrous tetrahydrofuran is addedover a 10 minute period. The reaction mixture is stirred for anadditional 15 minutes at 0C. and poured into a saturated aqueousammonium chloride solution. Benzene is added and the resulting mixtureis rapidly filtered through diatomaceous earth. The organic layer iswashed with a saturated aqueous ammonium chloride solution, with water,dried over anhydrous magnesium sulfate and evaporated to dryness. Thecrude product is layered with hexane and cooled overnight to yield 25 gof 17B-hydroxy-7amethylestr- 5-en-3-one acetate.

A 7 g portion of this material is dissolved in 170 ml of methanol towhich 7 ml of water and 10 ml of concentrated hydrochloric acid havebeen added. The solution is stirred for a period of 2 hours and pouredonto a mixture of ice-water. The ether extract is washed with water,dried over magnesium sulfate and evaporated to dryness.Recrystallization of the residue from acetonehexane yields the desiredl7fi-hydroxy-la-methylestr- 4-en-3-one acetate, which melts at 1081 10C.

EXAMPLE 4 17B-l-lydroxy-7a-methylestr-4-en-3-one The compoundl7B-hydroxy-7a-methylestr-S-en- 3-one acetate, prepared in accordancewith the preceding Example, is dissolved in 400 ml of methanolcontaining 9.5 g of sodium methoxide. The yellow solution is stirred for2 hours at room temperature under nitrogen and poured onto an ice-watermixture. The solid which forms is filtered and recyrstallized from anacetone-hexane mixture to yield 11.3 g (two crops) ofl7B-hydroxy-7a-methylestr-4-en-3-one having a melting point of 144-6C.

EXAMPLE 5 7a-Methylestr-4-ene-3a,17fidiol To 60 ml of a 1 molar solutionof lithium aluminum hydride in tetrahydrofuran, cooled in an ice bath,is added 7.88 ml (0.18 mole) of methanol. The solution is stirred for 30minutes following which 15 ml (0.06 mole) of tri-sec-butylborane isadded with additional stirring continued for 30 minutes at 0C. Thereducing agent prepared in this manner is cooled in a dry iceacetonebath to about 78C. and 5.75 g (0.02 mole) ofl7fl-hydroxy-7a-methylestr-4-en-B one in ml of tetrahydrofuran is slowlyadded. The reaction mixture is stirred for a period of 2 hours at thistemperature, warmed to 0C. and stirring continued for an additional 2hours. The reaction mixture is decomposed by the addition of 30 m1 of 3Nsodium hydroxide followed by 30 ml of a 30% hydrogen peroxide solution.Solid potassium carbonate is added and the tetrahydrofuran decanted. Thesolid residue is washed with 2 additional 150 ml portions oftetrahydrofuran. The combined tetrahydrofuran solutions are dried overanhydrous sodium sulfate, filtered and the solvent removed. The residueis taken up in a large volume of ether, filtered, concentrated andcooled. The 7a-methylestr-4-ene-3B ,l'iB-diol which separates on coolingis recrystallized twice from ether to yield 3.5 g of a white,crystalline material which melts at 96-102C.

The mother liquors from the above crystallizations are combined andevaporated to dryness. The residue is dissolved in methylene dichlorideand chromatographed on a silica gel column (60*200 mesh) which removessmall amounts of the remaining 3B-hydroxy isomer. The desired7a-methylestr-4-ene-3a,17B-diol is eluted with ether, and the eluaterecrystallized twice from ether to yield 1.3 g of finely divided, white,crystalline platelets melting at 17l6C.

Following essentially the same procedure but substi; tuting thecompounds 17B-hydroxy-7a-methylestr-4- en-3-one acetate, 7a-methyl17B-trimethy1siloxy-estr- 4 en 3-one and 17/3-( 1'-methoxycyclohexy1oxy)-7amethylestr-4en-3-one for thel'lB-hydroxy-7amethylestrA-en-B-one above, results in the formation of7a-methy1estr-4-ene-3a,17B-dio1 l'l acetate,7amethyl-l7fi-trimethylsiloxyestr-4-en-301-01 and 17B- 1methoxycyclohexyloxy)-7a-methy1estr-4-en-3a-ol, respectively.

EXAMPLE 6 'imMethyl-l 7B-(2'-tetrahydropyranyloxy )-estr-4-en-Phosphorous oxychloride is added to a solution ofl7fl-hydroxy-7a-methylestr-4-en-3-one in 2,3-dihydropyran. Afterstanding at room temperature for a period of 72 hours, the solution isdiluted with ether, washed with aqueous sodium carbonate followed by awater wash, dried over sodium sulfate and evaporated to dryness undervacuum. The residue which contains 7a-methyl-l7B-(2'-tetrahydropyrany1oxy)estr-4-en- 3 -one is dissolved intetrahydrofuran and reduced with lithium tri-sec-butylborohydridefollowing essentially the same procedure as in Example l. The residue istaken up in a large volume of ether and fractionally crystallized toremove the 3Bhydroxy isomer. The mother liquors are concentrated todryness. The residue is dissolved in a minimum amount of methylenedichloride, placed on a silica gel column and eluted with ether. Theeluate is evaporated to dryness and the residue crystallized from etherto yield 7a-methyl- 17B( 2'-tetrahydropyrany1oxy )estr-4-en-3a-o1.

EXAMPLE 7 7a-Methylestr-4-ene-3a, l 7B-diol diacetate EXAMPLE 87a-Methyl-3a-(1'-methoxycyclohexyloxy)estr-4-enl7B-ol acetate Thecompound 7a-methy1estr-4-en-3a,17fi-diol l7-acetate is dissolved inanhydrous dioxane and treated with pyridine. p-toluenesulfonate andcyclohex- 12 anone methyl enolether. Stirring is continued for a periodof 3 hours. The solvent is removed in vacuo and the residue iscrystallized from pentane resulting in the formation of the desired7a-methyl-3a-( l methoxycyclohexyloxy)estr-4-en-17,B-ol acetate.

EXAMPLE 9 Antiprogestational Activity Groups of 10 immature female ratsare treated over a 9-day period at age 28-36 days. One group of 10animals receives a daily dosage of mg/kg of progesterone. A second groupof 10 animals receives 40 mg/kg of progesterone and in additionconcurrently receives 1 mg/kg of the test compound, 7a -methylestr 4 ene3a,17B-diol. A third group of 10 animals serves as the vehicle controlgroup. At day 32 of treatment the right uterine horn of all animals istraumatized with a burred needle to simulate pseudo-implantation. Theanimals are sacrificed at day 37 of age and the uterine horns, both theuntraumatized control uterine horn and the traumatized horn areseparately weighed. The mean uterine horn weight increase of thetraumatized horn over the untraumatized horn in animals receiving thedrug plus progesterone was 26% of the corresponding progesterone treatedcontrol group, indicating that 7a-methylestr-4-ene-3a,l7,8;diolpossesses marked antiprogestational properties.

EXAMPLE l0 Antifertility Activity Commercially available female hamstersare mated and made pregnant by cohabitating with males overnight.Vaginal smears are taken on the following morning to see if they aresperm positive. A positive smear indicates day l of pregnancy. Testanimals are placed in groups of eight with two to three animals per cageunder conditions which enable a control of temperature, humidity, airflow, feed and water. The test group of animals are treated on days 3,4, 5, 6, 7 and 8 of pregnancy with the test compound by subcutaneousadministration. This period of treatment in the hamster roughlycorresponds in the fertile human female from a point prior toimplantation to a point subsequent to the ovarian-placental shift, i.e.,the point at which placental circulation is complete. Treatment invehicle only control groups are sacrificed on day 15 of pregnancy. Atnecropsy each animal is classified as pregnant with live feti, as notpregnant with resorbed uterine implantation sites, or as not pregnantwith no evidence of conception having taken place. The antifertilityactivity is indicated by a decrease in the total number of live feti inthe treatment group as compared to those in the vehicle control group.

Using this test system the compound 7a methy1estr- 4 -ene-3a,17B-dio1when administered subcutaneously at a dosage level of 1.0 mg/kg duringthe period of days 3 through 8 of pregnancy, exhibits a highantifertility activity with no live feti present at day 15, 1 day priorto parturition. in contrast thereto, when the compound7a-methy1estr-4-ene-3B,l 7B-diol is administered under identicalconditions of treatment and dosage, 29 live feti are obtained at day 15.Following the same procedure but increasing the dosage level of 10.0mg/kg the 3B-hydroxy isomer resulted in no live feti at day 15. Thus, inthis test system, 7a -methylestr-4-ene-3B,17B- diol demonstrates a10-fold increase in its antifertility wherein each R is selected fromthe group consisting of hydrogen, acyl having from 1 to 12 carbon atoms,lcycloalkenyl having from 5 to 8 carbon atoms, lmethoxycycloalkyl andl-ethoxycycloalkyl in which the cycloalkyl group has from 5 to 8 carbonatoms, Z-tetrahydropyranyl, and trialkylsilyl in which the alkyl groupcontains from l to 4 carbon atoms.

2. Essentially pure 7a-methylestr-4-ene-3a,l7B-diol.

3. A process of preparing a 7a-methylestr-4-ene- 3a,l7B-diol of claim 1which comprises reacting in a suitable solvent a7a-methylestr-4-en-IDS-substituted- 3one with a highly hindered lithiumtrialkylborohydride reagent at a temperature of from to 25C. to form asteroidal borane; hydrolyzing said steroidal borane; and recovering theproduct therefrom.

4. A process for preparing 7a-methylestr-4-ene- 3a,l7B-diol whichcomprises reacting l7B-hydroxy- 7a-methylestr-4-en-3-one with lithiumtri-sec-butylborohydride in accordance with claim 3.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 8 DATED December 23, 1975 lNVENTOR( I Joyce F Grunwel l andHarvey D Benson It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line +2, "endometrlam" should read endometrium";

Column 1, l lne 58, "designed" should read "designated"; Column l,

l lnes 22-23 "7 1"(' -dimethyl should read "7 17q-d imethyl Column 7, line 57, "21 1/2 1/2 should read 21 1/2"; Column 10, l lnes 38-39,"l'fg-hydroxy-h-methylestr-5-en-3-one" should read "17BhydrOy-7r1methylestrl-en-3-one"; Column 12, l lne 47, "in" should read "and";Column 12, l lnes 67-68, 'T -methylestrh ene-3B, 175 -d iol should read"Y -methylestrl-ene-3 17B -dlol Column 14, l ine 13, claim 3, "3one"should read "3-one" Signed and Scaled this Thirtieth Day Of November1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner nflarenrsand Trademarks

1. AN ESSENTIALLY PURE 7A-METHYLESTR-4-ENE-3A,17B-DIOL HAVING THEFORMULA
 2. Essentially pure 7 Alpha -methylestr-4-ene-3 Alpha ,17 Beta-diol.
 3. A process of preparing a 7 Alpha -methylestr-4-ene-3 Alpha ,17 Beta -diol of claim 1 which comprises reacting in a suitable solventa 7 Alpha -methylestr-4-en-17 Beta -substituted-3one with a highlyhindered lithium trialkylborohydride reagent at a temperature of from-80* to 25*C. to form a steroidal borane; hydrolyzing said steroidalborane; and recovering the product therefrom.
 4. A process for preparing7 Alpha -methylestr-4-ene-3 Alpha , 17 Beta -diol which comprisesreacting 17 Beta -hydroxy-7 Alpha -methylestr-4-en-3-one with lithiumtri-sec-butylborohydride in accordance with claim 3.